1. Field of the Invention
The present invention generally relates to an electic fan assembly capable of directing a current of air in any adjusted direction and, more particularly, to an electric fan assembly suited for use in an air-conditioner.
2. Description of the Prior Art
One prior art electric fan assembly which appears to be conceptually similar to the present invention is illustrated in FIGS. 1 and 2 of the accompanying drawings in perspective and endwise sectional views, respectively. Referring to FIGS. 1 and 2, the prior art electric fan assembly comprises a base plate 1 having a support leg 2 rigidly mounted thereon. A generally cylindrical motor casing 3 is rigidly mounted on the top of the support leg 2 with its longitudinal axis lying parallel to the base plate 1. Casing 3 houses therein an electric drive motor (not shown) having its drive shaft 6 extending outwardly from the motor casing 3 in parallel to the base plate. A power control switch 4 is installed on the motor casing 3 for selectively energizing and deenergizing the drive motor, as is well known to those skilled in the art. The fan assembly shown in FIGS. 1 and 2 also comprises a generally cylindrically cross-flow fan 5 mounted coaxially on the drive shaft 6 for rotation together therewith. A rear baffling plate 7 is so supported by the motor casing 3 and so shaped as to partially encircle the cross-flow fan 5 over an angular distance approximately corresponding to half the outer diameter of the cros-flow fan 5. A stabilizer bar 8 extends in parallel spaced relation to the cross-flow fan 5 for angular movement about the drive shaft 6 and is positioned on one side of the cross-flow fan 5 opposite to the baffling plate 7.
In the construction described with reference to FIGS. 1 and 2, the switching-on of the power control switch 4 results in rotation of the cross-flow fan 5 in one direction, for example, the clockwise direction about the drive shaft 6. As the fan 6 is so rotated, air is drawn towards the baffling plate 7 through a suction opening defined on the trailing side with respect to the direction of rotation of the fan 5 and is, after having been stirred to form a current of air, discharged in a predetermined direction through a discharge opening on the leading side with respect to the direction of rotation of the fan 5, substantially as shown by the arrow-headed chain lines in FIG. 2. During the flow of the air in the manner shown by the arrow-headed chain lines, a vortex of air is generated at a region, shown by the circle V in FIG. 2, between the fan 5 and the stabilizer bar 8, which vortex V moves relatively around the fan 5 together with the stabilizer bar 8 when the latter is angularly moved to adjust the direction of flow of the air current emerging from the fan assembly.
While the suction and discharge openings in the fan assembly of FIGS. 1 and 2 may be considered as defined between the leading edge of the baffling plate 7 and the stabilizer bar 8 and between the trailing edge of the baffling plate 7 and the stabilizer bar 8, respectively. The adjustment of the position of the stabilizer bar 8 relative to the fan 5 or the baffling plate 7 results in a change in width of the suction and discharge openings in opposite relation. Therefore, the pattern of distribution of the expelled air current varies with the position of the stabilizer bar 8, as readily may be understood from FIG. 2.
The prior art fan assembly of the construction shown in FIGS. 1 and 2 is satisfactory and effective in that the direction of flow of the expelled air current can be adjustable merely by angularly moving the stabilizer bar 8. However, it has been found that the velocity of flow of the expelled air current tends to vary with the adjusted direction of blow of the expelled air current, thereby posing some disadvantages and inconveniences. Thses disadvantages and inconveniences are pronounced specifically where the concept embodied by the construction shown in FIGS. 1 and 2 is employed in a domestic space heating and/or cooling device, particularly a domestic air-conditioner having a heat pump system, to make a forced draft of air available.
Specifically, while it is generally required that the expelled air current must reach as far as possible in order for a house room to be uniformly cooled or heated when the air-conditioner is operating in a cooling mode or a heating mode, respectively. The design and structure such as employed in the prior art fan assembly cannot achieve the above described requirement satisfactorily.